1. Field of the Invention
This invention generally relates to manufacturing ophthalmic lenses, and more specifically to methods and systems for recording data taken during the manufacturing of ophthalmic lenses such as contact lenses.
2. Background Art
Over the last several years, procedures have been developed to mold contact lenses on a high speed automated basis, and for example, such systems are disclosed in U.S. Pat. Nos. 5,555,504 and 5,702,735 and U.S. patent application Ser. No. 09/305,886, filed May 5, 1999 for “Mold and Molding Machine For Making Ophthalmic Devices.” In these systems, generally, a group, or batch, of lenses is formed by sandwiching a monomer between a set of front and back mold sections. The monomer is polymerized, thus forming the lenses, which are then removed from the mold sections, further treated and packaged for consumer use.
In this process, the mold sections and the lenses are transported through a number of stations or zones. For instance, the processing system may include filling, pre-curing, polymerizing, de-molding, and hydration stations. In order to be sure that the manufactured lenses are suitable, various parameters must be maintained within given ranges at each of these stations; and, accordingly, these parameters are carefully monitored at the stations.
The number of monitored parameters can be quite large, and for example, three to eight parameters may be monitored at each station. Also, with previous systems, all of these parameters were recorded so that a complete history of the processing parameters was recorded and available for every manufactured lens. Because of the large number of lenses that are made using these procedures and because of the large number of monitored parameters, this resulted in an extremely large database. For instance, a full print-out of the process parameters recorded while a single batch of lenses was made might be three pages long, and over the course of a year, 5000 batches of lenses may be manufactured on a system. This results in an enormous amount of data, which is expensive to organize and to store. Moreover, government regulations require that a paper copy of each device history record be provided for each batch of lenses when the batch is shipped from the manufacturing site. Again, because of the large number of lenses made and because of the enormous amount of recorded data, finding the proper paper record for each lens and matching that paper work with the lens can be expensive, time consuming and also can significantly delay release of the product.
In addition, because of the significance of data recorded during the lens fabrication process, it is important to prevent the inadvertent or intentional loss or alteration of data. Heretofore, loss of data is usually solved with audit trails implemented by using the built in functionality of the database management system. A problem with this approach, in the case of conventional data base management systems, is that the audit trail includes only the type of transaction (insert, update, delete), the table affected, the time stamp of the transaction, and the user id making the transaction. This audit trail does not include a “before” and “after” snapshot of the data affected. This eliminates the ability of reports based on this data to provide a complete picture of what happened during the fabrication process.